Clock power-device



" Feb. 2, 1965 FIG.

l fi f I M 2 F r.

I; BE so 1 I I I O 2 AT! 4 FIG! 3b Filed Aug. 31, 1954 2 ATr I 3 i 2 ATr 4 FIG. 4

95 BC A BE Filed Aug. 31, 1954, Ser. No. 453,392 Claims priority, application France, Sept. 17, 1953, 654,809, Patent 1,090,564 8 Claims. (Cl. 318-127) This invention relates to electrical apparatus and, more particularly, electrical time-apparatus (clocks and watches) which are to be powered from a weak source of direct current such as a small cell or a storage battery; more particularly still, it relates to the prime movers of the electromagnetic impulse type which incorporates at least one movable permanent magnet.

The apparatus of this type now in use comprises switches with intermittent electrical contacts get worn out fairly quickly andthe operation of which is irregular'and" not reliable. Moreover, the control of such switches at very precise instants require mechanisms, the design and the adjustment of which are delicate and which introduceirregular losses'of energy due to impact and friction effects, whereby the steadiness in the operation of the time mechanisms is greatly impaired.

One object of the invention is to provide a power de- 'vice which is reliable in operation and which is of simple design incorporating no intermittent electric contacts.

Another object of the invention is to provide a power device of small dimensionsthough highly efficient, adapted to be accommodated within a watch-case for instance.

This invention is characterized by the fact that the electrical contact which supplies the driving electromagnet in the conventional devices is replaced by an electronic amplifier of the type known under the name of junction transistor, i.e. an amplifier with a solid body comprising no heated filament and which may be put instantaneously in operation under the action of a very small electric power, under a relatively very low voltage.

Such an amplifier constitutes a very consistent and sensitive relay and operates under the influence of a so-called control coil or release coil winding which is located near the movable magnet. This winding is connected in series with-the variable resistance between the emitting electrode and the control electrode of the transistor whereby the whole assembly forms an uninterrupted releasing circuit. The movement of the permanent magnet induces a weak alternating electromotive force into the control coil, and, when the voltage applied to the transistor reaches a sufficient value and the suitable sign or direction, weak currents flow in the release circuit and act upon the conduction of the transistor portion which comprises the collecting (or output) electrode in order to cause the source of electric power to send short unidirectional currents into a power electromagnet. The armature of this electromagnet may be constituted by the movable magnet hereinabove mentioned.

Other and further objects and advantages of the invention will be apparent to those skilled in the art from a consideration of the following description of three specific embodiments of the invention as applied to the following apparatus:

. (1) Clock with a pendulum kept in motion by electromagnetical means;

(2) Watch with a small circular magnetized balance wheel which actuates a chronometric counter;

(3) Time mechanism with an escapement adapted to be wound up by a separate motor which comprises a permanent magnet able to rotate in one direction only.

Said embodiments are shown by way oi" examples, in the accompanying drawings, in which:

nited States i a tent Gfice FIG. 1 illustrates the power device according to the invention as applied for keeping a pendulum in motion;

FIG. 2 shows. in greater detail, the wiring diagram of the device illustrated in FIG. 1;

FIGS. 3a and 3b diagrammatically illustrate, in front and side elevation views respectively, a power device according to the invention as applied to the driving of a circular balance wheel;

FIG. 4 diagrammatically shows a rotary motor designed according to the invention and able to actuate, either directly or indirectly, the hands of a time instrument;

FIG. 5 shows in greater details the construction of a watch with a balance wheel serving as an oscillating motor designed according to the invention.

In every figure of the drawing, the electronic devices adapted to distribute the power electromagnetic impulses have been diagrammatically identified either by the general symbol ATr of an amplifier relay (comprising two input terminals 1-2, two output terminals 3-4 and a source of power G), or by the particular symbol of a sistor element Tr of the known type called PNP junction type" the electrodes of which are identified as foliows:

e-emitting electrode b-control electrode (or base) ccollecting electrode (or output) As a first instance, FIG. 1 shows the application of. the invention to an electromagnetic clock of a known type.

This clock has a pendulum the main weight M of which is fitted with a ferromagnetic cross bar F and a bipolar magnet A in the shape of an arc transversally arranged and the magnetic poles of which are concentrated at N, and S The pole N of the magnet A receives successive power impulses from a hollow coil BE which is called the sustaining coil and which is connected in a circuit comprising a cell G. The periodic energizing of this coil is the object of the invention.

According to the invention, a stationary auxiliary coii BC which is called the control coil is arranged about the magnet A. The turns of this coil embrace the pole S when the pendulum is but slightly moved away from the vertical and, therefore, they are subject to a strong radial magnetic field.

The leads of the coil BC are connected to the input terminals 1 and 2 of an amplifying relay ATr of the socalled junction transistor known type the features of which have been stated hereinabove.

The output terminals 34 of this amplifier are connected to the stationary sustaining coil BE which embraces the pole N of the magnet, and the energy required for operation is supplied by the cell G under the condi tions hereinunder stated:

When the pendulum oscillates, the turns of the stationary coil BC cut the radial lines of magnetic flux set up by the pole S of the magnet A. This results in an alternating 'electromotive force U to be induced in the C0ll BC and which reaches a maximum every time the "pendulum passes the vertical (this position being called balance position or dead point as illustrated in FIG. 1). This electromotive force which is due to the move ment of the magnet A, constitutes the input signal to the amplifying relay ATr.

From the known properties of the amplifiers of this type it ensues that a current I may be derived from the outputterminals 3-4 and flow through the coil BE only when the voltage U of the input signal (or control voltreaches a predetermined value with a given sign. Under such conditions, the current I is delivered every time the pendulum moves a short distance near its posh tion of equilibrium in the direction h. The stationary members BC and AW, therefore, have the function of 3 'a self-sustaining switching mechanism .actuated by the :strokes of the pendulum in one direction only.

Owing to the presence of the amplifier ATr, the mean .electric power of the currents I delivered by the cell G is greater than the passive power consumed in inducing the releasing currents i. Under these conditions, the osciilaltions of the pendulum are sustainedand thependulum is even able to directly-actuate a chronometric counter with hands.

The inner connections of the amplifying relay ATr .may be effected in various ways, for example, use may be made of the connections already proposed for amplifying the weak currents obtained by 'means of magneto electric microphones or record players.

FIG. 2 diagrammatically illustrates a particular schermatic for an amplifier particularly advantageous when the invention is applied to electric clocks and watches. In this embodiment, a single junction transistor element Tr which,- in the example illustrated, is of the so-called PNP type provided with three terminals, ensures the periodic energization of the sustaining coil BE by means of the cell G. t

According to the invention, the control coil BC is core nected to the electrodes b (base) ande (emitting) of the transistor while the sustaining coil BE is connected to the electrodes c (collecting) and e (emitting) through the cell G, the positive terminal of which is connected to the electrode e.

Experience shows that the characteristics and the positions-of the coils BC and BE and of the transistor Tr may be selected. so as to effect an isochronal movement of a heavy power pendulum of which the amplitude of oscillation is automatically regulated by the etfect of the phenomena described in detail hereinafter.

It is but for a given polarity of the ele'ctromotive force U and above a predetermined voltage level that the internal resistance of the portion of the transistor between the electrodes b and e lessens much and allows the re- .lease current i to flow. By virtue of the so-ca1led transistor effect property, the current i also reduces the internal resistance of the transistor between theelectrodes e and c and, therefore, the sustaining current i circulates in the circuit which comprises the cell G and the coil BE.

It will be found'that the magnet A may, without any disadvantage, oscillate slowly and-with a short amplitude,

, since a small voltage'U (below 0.1 volt) is suflicient for releasing from the cell G a current I of about 1 milliampere under the voltage of the cell. An instantaneous electric power of about 0.5 milliwatt received by the coil BE is sufiicientfor operating the clock under satisfactory conditions. Since the current IflOWs through 'BE only when the pendulum passes the position of equilibrium, the conditions which are deemed the best inclock technique for ensuring isochronal oscillations of a clock pendulum or balance wheel are thus obtained and the period of oscillation is not substantially disturbed by small variations in the amplitude of the alternating movement.

Te'sts'have proved that, when use is made of a coil with more than 5,000, turns, the counter-electromotive force E induced inthis coil reaches a value above 0.5 volt. It will be noted that an increase in the passive resistance results in the amplitude of the oscillations tending to decrease as well as the electromotive forces induced in the coils BC and BE by the magnet A. The decrease of these electromotive forces has two favorable etfects,

namely:

(l) A decrease of the damping effect due to the 'pro duction of the induced control current i-(resistant'power);

(2) An increase .in the power impulse, due to the decrease of the counter-electromotive force E induced in BE (driving power).

The decrease .in the resistant power and the increase in the driving power limit the reduction in the amplitude of the pendulum and an 'operaticn with an amplitude automatically stabilized is thus obtained, that is to mechanical power is the following:

A wherein E denotesthe counter-electromotive force which is set up by induction within the driving coil, andU the voltage of the source'of electricv power. The smaller the work accomplished in onesecond andthenearer'to the ideal value 1 the efficiency is, and when-theelectric motor runs at no load, E is very'near U.

The motor formed-by a magnet A periodically energized througha transistor, as illustrated in FIGS.'1 and2, has the feature herein above indicated and the reduction in the damping forces due to the omission 'of'theself-sustaining contact makes it possible to cause the counter-else tromotive force E included inthe coil BEto' be very near the voltage U of the cell G. Hence, the eificiency N gets nearer the maximum value 1. Thecurrent I delivered, according to Ohms lawz (R=resistance 'of the circuit) becomes very-weak.

Under such conditions, the life of the cell is'very long. Experience has shown that a pendulum properly designed, according to FIG. 1, which-oscillates :with a short amplitude, is easily sustained with a mean electric power rated below 10 microwatts.

As already seen hereinabove, the increase in the ratio E/ U also makes it possible to improve the stability of the amplitude.

The driving device illustrated in FIGS. 12 is applicable to high precision clocks constituted by a so-called free regulating pendulum (i.e. deprived of'any mechanism) cooperating with a dependent clock which actuates the hands.

In fact, the alternations of the electromotive force induced in the coil BC may successively act'upon the amplifier ATr and upon an auxiliary amplifier adapted to supply a dependent clock.

This driving device is also suitable for sustaining the various types of oscillating'or vibrating regulating members to which it is possible to add a magnet. Particularly, it may be applied to the known type of electric watches the regulating and drivingmember of whichis constituted by a'small balance wheel, associated with a spiral spring.

FIGS. 3a and 3b diagrammatically illustrate a device of this type.

The oscillating balance wheel is formed by two discs A and A are made of a material with a very strong mag netic field and only the portions thereof indicated as at N 5 and N 5 arepermanently magnetized. In the other portions thereof, the groups of molecules called Weiss range are left in disorder. The parts A and A of the balance wheel only at the periphery thereof have-active poles N and S highly concentrated, facing each other whereby the balance wheel forms an astatic unit. The stationary coil adapted to set upthe-periodic signal which releases the powerimpulses is formed by a fiatcoil BCci copper wire arranged between the adjacent coaxial magnets A and A as illustrated in FIG. 3, wherein the baiance wheel associated with the spiral spring 5 is shown in its rest or equilibrium. position.

As in the arrangement illustrated in FIG. 1, the amplifier ATr is connected, on one hand, to the coil BC and, on the other hand, to at least one driving electromagnet BE of any suitable type able to impart a short driving impulse to the balance wheel to be sustained.

The power device of FIGS. 3a and 3b operates as fol= lows:

The emissions of the input current which release the power impulses occur as the magnetic poles N and 3; move at high speed in the direction 1 passing a bundle of active conductors which belong to the coilBC.

The source of electric power G and the transistor reiay ATr may simultaneously actuate not only the coil BE but also the coil BR of a receiving chronometric counter.

The power device according to the invention may also be used for sustaining the continuous rotary motion in one direction only of a magnet A mounted on a spindle 0.

FIG. 4 diagrammatically illustrates a device of this type in which the rotary magnet A is constituted by a disc ot a material with a strong magnetic field.

This disc A has at least two peripheral poles N and E3 and on the sides thereof are arranged two stationary tlat coils BC and BE connected with the amplifier ATr and the source of electric power as indicated in MG. 4. It will be seen that the wiring diagram is the same as that of FIG. 1.

Preferably, each coil has a curved shape and a width such that the active conductors which cut the lines of magnetic flux (conductors parallel with the spindle O of the disc) are very near the peripheral poles of the magnet.

The operation of the motor of FIG. 4 is as follows:

When the permanent magnet A turns, the coil BC has a variable magnetic flux and an alternating electromotive induction force is developed in this coil which generates at certain intervals the input signal received at terminals 1 and 2 from the amplifier to the transistor ATr.

It is well known that such an amplifier can be set so as to be sensitive only to an input current i having a predetermined direction. The maximum active current exists while the line of the NS poles is at a predetermined position in relation to the coil BC (for example in the vicinity of the NS orientation indicated by the arrows on the magnet A of FIG. 4).

During flow of input current i, the amplifier ATr delivers to terminals 3 and 4 ari output current I which crosses coil BE. As a result of the amplifying properties of the transistor, the output current I can develop a relatively high electric force. By suitably connecting coil E it is possible to have current I exert a considerable torque or couple on the magnet-A. Under these circumstances the magnet A turns with a continuous movement as it receives motive impulses at each passage in the vicinity of the position of FIG. 4. The dead-centers or dead-points are cleared by virtue of the inertia of the rotor.

The device illustrated in FIG. 4 constitutes a motor without commutator which is able to rotate under a very weak electromagnetic torque since all the passive resistances are extremely weak. It is possible to eliminate the influence of the external magnetic fields by providing a shielding BL aboutthe magnet A and the coils BE and BC, in the shape of a tube coaxial with the spindle O and made of a mild ferro magnetic alloy with a high permeability.

The transistor motor of FIG. 4 may advantageously be substituted for other types of rotary motors previously used or proposed in the design of clocks and watches with electric wind-up.

The motor of FIG. 4 may also be used (FIG. 7) for directly driving the hands 23 of a clock by means of a reducing geartrain 24. In this case, it is necessary that the rotational speed of the magnet A be made uniform. Such a result may be obtained by the use of various speed regulators of known construction (centrifugal force regulators, conical penduiums, magnetic escapements which is already known.

vibrating blades or pendulums, etc). For examp well-known regulator or governor consists of a vibr plate suitably housed and supporting a magnet, uricestablishes, as is known, a magnetic coupling or conaee-= tion between the rotation of the magnet and the vibration of the plate, the frequency of rotation of the latter regulates the rotation of the magnet.

FIG. 5 illustrates a particular embodiment of the which is diagrammatically represented in FIG. balance wheel is constituted by a disc A magnetized in direction parallel with a diameter NS; it moves inside 11. wide hollow coils BC and BE arranged on eachside and at a short distance from the spindle 0.

These coils are connected to a transistor element Tr as in the wiring of FIG. 2. The clamping ring of the spiral spring 13 is oriented on the spindle O in such a manner that the line NS is parallel with the plane of the coils BE and BC.

The balance wheel thus obtained is sustained in the same manner as that of FIG. 3 but the electromagnet BE, in this figure, is constituted by a mere coil which exerts an intermittent electromagnetic torque upon the magnet The balance wheel in alternating motion chronometric counter of a known type: for instwu moves a fork 14 provided with a driving escapement 6 adapted to rotate an escapement wheel 7, step by a. The latter drives, through a train of gears, the spindle which carries a seconds hand 9. The other two ha. 10 and 12 are driven by gears and a minutes train 11.

Many modifications may be made in the devices herein above described without the scope of the invention departed from.

The power devices illustrated in the drawings may further comprise synchronizing coils the operation of For instance, the pendulum of FIG. 1 having an own period near T it is possible to impose a compulsory period T which is strictly equai to that of a remote time-keeper or a rhythmed time-signal. Such a result is obtained, in particular, by means of an additional coil BS receiving a pulsating synchronizing current with a period T.

Either the period or the angular velocity of magnet A may be corrected by means of a weak synchronizingsignal acting in the entrance 1-2 to the amplifier ATr.

The power devices and the winding devices designed in accordance with the invention are applicable to the masterclock, the clocks, and board watches for tripping and warn ing, sounding clocks, recorders, frequency standard indicators, etc. Of course, the device of FIG. 4 may be used for rotating various apparatus other than clocks, such gramophone records, records of speaking clocks, men.- bers of stroboscopic apparatus, gramophones, gyroscope rotors, etc.

What we claim is:

1. In an electromagnetic impulse power device of type including at least one movable permanent magnet, the construction comprising an isochronal pendulum, a bipolar bar-like magnet transversely carried by said isochronal pendulum, an electronic amplifier of the transistor type having input and output terminals, a source of electric power feeding said electronic amplifier, a first stationary coil surrounding said bipolar magnet, and connected to the input terminals of said electronic amplifier and positioned with respect to said bipolar magnet to set up induwd control currents under the action of the movement oi? said permanent magnet relative to said first coil, and a second coil surrounding said permanent bipolar magnet and adapted to impart successive driving impulses to said permanent bipolar magnet, said second coil being con nected to the output terminals of said electronic amplifier.

2. An oscillating commutatorless DC. motor comprising, an electromagnetic field structure, a rotor comprising a permanently magnetized bar'mounted for rotation-with respect to said field structure, at ieast one driving winding said field structure, at least'one control winding ings to bias said transistor to conduction when said rotor rotates, means connected to said transistor and said driving winding to produce a flow of current in said driving windings when said transistor is conductive and means to urge said rotor to a normal position with respect to said field structure and to resist movement from said normal position, said means serving to limit the movement of said rotor under urge of said driving winding to thereby cause said rotor to oscillate about said normal position under control of said windings and said transisters.

3. A direct current electric motor comprising, in combination, a stationary electromagnetic field structure, a permanently magnetized bar mounted for rotation within the said field structure, at least one driving winding, on said field structure, at least one control winding on said field structure, and a circuit including a source of direct current, at least one transistor connected with its emittercollector terminals in series with said driving winding, and its base terminal connected to said control winding, said transistor being rendered conductive by the current in duced in said control winding in response to rotation of said bar to supply current from said source to said driving winding to thus produce magnetic pulses in said field structure for rotating said rotor bar.

4. A direct current motor as claimed in claim 3, char acterized in that cessation of rotation causes said transistor to become non-conducting thereby reducing the current in said driving winding to zero.

5. A direct current electric motor comprising, in combination, a stationary electromagnetic field structure, a permanently magnetized bar mounted for rotation within the said field structure, at least one driving winding on said field structure, at least one control winding on said field structure, and a circuit including a source of direct current and at least one transistor connected to said driving and control windings, said transistor being rendered selectively conductive in response to rotation of said bar to supply current from said source to said driving winding periodically to thus produce magnetic pulses in said field structure to cause rotation of said rotor bar.

6. In an electromagnetic impulse driving device of the type including at least one substantially isochronal osciland a second coil connected to the output terminals of said electronic amplifier to receive the output of said amplifier and effective to impart periodic driving impulses to said permanent magnet and said oscillatory member.

7. An oscillating commutatorless DC. motor comprising, an electromagnetic field structure, a rotor comprising a permanently magnetized element mounted for a ro tation with respect to said field structure, at least one driving winding on said field structure, at least one control winding on said field structure, at leastone transistor, means connecting each said transistor to one of said control windings to bias said transistor to conduction when said rotor rotates, means connected to said transistor and said driving winding to produce a flow of current in said driving windings when said transistor is conductive and spring means to urge said rotor to a normal position with respect to said field structure and to resist movement from said normal position, said means serving to limit the movement of said rotor under urge of said driving winding to thereby cause said rotor to oscillate about said normal position under control or said windings and said transistors.

8. A timing movement comprising at least one s'nh stantially isochronal movable member having at least a permanent magnet portion thereon, an electronic circuit including a transistor having input and output terminals, means for connecting a source of electric power for energizing said electronic circuit, afirst coil connected; to said input terminals of said transistor and positioned with respect to said permanent magnet portion to have control signals induced therein for controlling and causing a periodic ouput from saidtransistor in response to the movement of said permanent magnet portion relative to said coil, and a second coil connected to said output terminals of said transistor to receive saidperiodic ou put thereof and effective in response thereto to impart periodic driving impulses to said movable member.

References Cited by the Ear UNITED STATES PATENTS 7 1,560,056 11/25 Horton 58-265 2,472,249 6/49 De Giers et al. 58-23 2,640,978 6/53 Claesson et al 307--88.5 X 2,652,460 9/53 Wallace 58-23 2,680,160 6/54 Yaeger. 2,719,944 10/55 Brailsford. 2,769,946 11/56 Brailsford 318l28 FOREIGN PATENTS 375,188 5/07 France. 601,712 5/48 Great Britain.

ORIS L. RADER, Primary Examiner. EXCELLENZA L. MORSE, JOSEPH P. STRIZAK,

I Examiners. 

1. IN ELECTROMAGNETIC IMPULSE POWER DEVICE OF THE TYPE INCLUDING AT LEAST ONE MOVABLE PERMANENT MAGNET, THE CONSTRUCTION COMPRISING AN ISOCHRONAL PENDULUM, A BIPOLAR BAR-LIKE MAGNET TRANSVERSELY CARRIED BY SAID ISOCHRONAL PENDULUM, AN ELECTRONIC AMPLIFIER OF THE TRANSISTOR TYPE HAVING INPUT AND OUTPUT TERMINALS, A SOURCE OF ELECTRIC POWER FEEDING SAID ELECTRONIC AMPLIFIER, A FIRST STATIONARY COIL SURROUNDING SAID BIPOLAR MAGNET AND CONNECTED TO THE INPUT TERMINALS OF SAID ELECTRONIC AMPLIFIER AND POSITIONED WITH RESPECT TO SAID BIPOLAR MAGNET TO SET UP INDUCED CONTROL CURRENTS UNDER THE ACTION OF THE MOVEMENT OF SAID PERMANENT MAGNET RELATIVE TO SAID FIRST COIL, AND A SECOND COIL SURROUNDING SAID PERMANENT BIPOLAR MAGNET AND ADAPTED TO IMPART SUCCESSIVE DRIVING IMPULSES TO SAID PERMANENT BIPOLAR MAGNET, SAID SECOND COIL BEING CONNECTED TO THE OUTPUT TERMINALS OF SAID ELECTRONIC AMPLIFIER. 